Effects of Octacosanol During Taekwondo Training: Complete Statistical Analysis

1. Trial at a Glance

This page covers the registry results for Effects of Octacosanol During Taekwondo Training (NCT03557476), a randomized na study. The primary outcome is Triglycerides.

2. Clinical Question

3. Trial Design

This was a randomized, double-masked, parallel-group trial of octacosanol versus placebo. Enrollment was 26, and the primary outcome summaries report 13.0 participants in each arm. In a parallel-group design, participants are assigned to one study group and receive that group’s intervention rather than crossing over between interventions. Random allocation is intended to reduce systematic differences between groups, while masking is intended to limit the influence of knowing the assigned intervention on participants or other people involved in the study. The registry record does not report the sequence-generation method, allocation concealment, or who specifically was masked.

The octacosanol group took two capsules daily for six days, one after the morning meal and one after the afternoon meal. Each capsule contained 20-mg of refined octacosanol powder from sugar cane. The placebo group took a placebo pill twice daily in place of the supplement. The primary endpoint was mean plasma triglyceride level at six days. The three posted secondary measures were malondialdehyde, superoxide dismutase, and glutathione peroxidase, also assessed at six days.

The study status is completed. The record identifies the phase as NA and names Kosin University as sponsor. It gives a start date of 2017-08-01 and a primary completion date of 2018-03-01. Those record dates do not, by themselves, describe the duration of an individual participant’s follow-up. A protocol, the trial’s original sample-size justification, the planned analysis methods, and details of participant flow are not reported in the registry record.

4. Participant Flow and Accounting

The registry reports how participants moved through each stage of the study. All counts below are exactly as posted; missing counts are not inferred from other stages.

Overall Study

5. Baseline Characteristics

The table reproduces the baseline characteristics posted in the registry, which describe the participants analysed at baseline and help show whether the randomized groups were comparable.

6. Primary Endpoint

The registry lists the primary outcome as Triglycerides, measured over 6 days.

The primary endpoint was plasma triglyceride level, expressed in mg/dL, summarized as a mean with standard deviation at six days. Triglycerides are a type of lipid measured in plasma, so this endpoint addresses the lipid-profile concern described in the study summary. The summary places the question in the context of rapid weight reduction paired with high-intensity exercise among Taekwondo players.

A mean describes the central value of the measurements in a group. A standard deviation describes how dispersed individual measurements are around that mean; it is not the same as the uncertainty in the estimated group mean or in the between-group difference. Comparing the endpoint means gives a direct summary of how the groups’ reported triglyceride levels differed at the stated timeframe.

The endpoint description identifies a level, not a change from baseline. Baseline triglyceride results and a baseline-adjusted comparison are not reported in the registry record. Accordingly, the posted group means should be interpreted as endpoint summaries rather than evidence about the amount of change within either group. The record does not report details of the laboratory assay or the timing of blood collection relative to exercise or meals.

7. Results Posted in the Registry

• Octacosanol: mean 34.90 versus 110.00 on control; difference -75.10 (95% CI -81.21 to -68.99), standardized effect d = -9.44; z-test p = <0.001.

8. Secondary Efficacy Endpoints

The registry also posts results for secondary outcomes. For each outcome below, the endpoint type, the test applied to the posted summary statistics, the result and its interpretation are given in turn. Secondary endpoints are usually not adjusted for multiple testing, so they support rather than confirm the primary finding.

Malondialdehyde

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Octacosanol: mean 0.25 versus 0.93 on control; difference -0.68 (95% CI -0.76 to -0.60), standardized effect d = -6.16; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically lower for Octacosanol than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Superoxide Dismutase

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Octacosanol: mean 1,450 versus 1,010 on control; difference 440.00 (95% CI 328.83 to 551.17), standardized effect d = 3.04; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Octacosanol than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

Glutathione Peroxidase

• Endpoint type: Continuous: a mean value per participant, compared as a difference in means.
• Test: Unadjusted two-sample z-test for the difference in means, using the posted standard deviations.
• Result:
  • Octacosanol: mean 66.90 versus 47.10 on control; difference 19.80 (95% CI 11.91 to 27.69), standardized effect d = 1.93; z-test p = <0.001.
• Interpretation:
  • The 95% confidence interval excludes no difference, so the mean is statistically higher for Octacosanol than for the control. This is an unadjusted, secondary comparison, so it is suggestive rather than confirmatory.

The secondary outcomes form a broadly coherent pattern in the posted summaries: malondialdehyde was lower in the octacosanol group, while superoxide dismutase and glutathione peroxidase were higher. These measures relate to oxidative stress, a concern identified in the study summary. Their direction is therefore consistent with the general biological theme of the trial and complements the primary lipid measure rather than measuring the same construct.

That coherence does not establish a common mechanism or demonstrate that the primary result caused the secondary findings. Each endpoint is a separate measurement, with its own variability and potential measurement limitations. The record reports all three at the same six-day timeframe, but does not provide baseline values or describe whether the comparisons were adjusted for other variables.

The secondary comparison p-values are unadjusted, and the registry record does not report a multiplicity strategy or a prespecified hierarchy for interpreting outcomes. When multiple outcomes are tested, the chance of seeing at least one apparently strong result can increase. Without a reported adjustment or analysis plan, these findings carry less confirmatory weight than a single prespecified primary comparison and are best treated as supportive, not definitive.

There are no reported analyses listed for the secondary outcomes in the registry record. The available group summaries and unadjusted comparisons can describe the posted pattern, but the record does not establish how the outcomes were selected, whether all measured outcomes were reported, or how missing observations were handled. Further interpretation should therefore remain limited to the observed endpoint summaries at the stated timeframe.

Secondary outcomes registered for this trial, for reference (only those above were recalculated):

• Malondialdehyde
• Superoxide Dismutase
• Glutathione Peroxidase

9. Statistical Interpretation

10. Statistical Methods Explained

What does the mean difference represent?

The comparison is an unadjusted difference between the two endpoint means. The octacosanol mean is compared with the placebo mean, so the contrast is expressed as octacosanol minus placebo. For triglycerides, the reported means are 34.9 mg/dL and 110.0 mg/dL, respectively, and the stated mean difference is -75.1 mg/dL. A negative value means the first group’s mean is lower than the comparator group’s mean. The subtraction describes the endpoint contrast; it does not represent a baseline-to-endpoint change.

In general, an unadjusted comparison uses the group summaries without accounting for other variables. It is a straightforward way to describe the observed contrast, but it does not make any allowance for baseline differences or other prognostic factors. The registry record does not report a covariate-adjusted model or a baseline-adjusted analysis.

What does standard deviation describe?

The registry record reports each group’s mean and standard deviation. In general, standard deviation describes the spread of individual observations around their group mean. A larger standard deviation indicates more dispersion among individual observations, while a smaller one indicates that observations are more clustered around the mean. It is not a confidence interval and should not be read as the range containing every participant’s value.

Standard deviations are useful for understanding variation within groups and are part of the information used in a comparison of means. They do not, alone, convey the precision of the difference estimate. Precision also depends on the amount of information in the group summaries and on the comparison method.

How should the confidence interval be read?

The interval for the primary mean difference extends from -81.21 to -68.99 mg/dL. In general, a confidence interval gives a range of values compatible with the observed data and the method’s assumptions. A narrower interval indicates greater precision than a wider interval, while the interval’s position describes which contrasts remain compatible with the data under that method. The confidence level used for the posted interval is not reported in the registry record, so it should not be inferred.

A confidence interval does not include all uncertainty about a study. It reflects statistical uncertainty under the calculation used, not potential bias from missing data, measurement procedures, or selective reporting. It also does not directly establish whether a difference is important in practice; the registry record does not report a threshold for clinical importance.

What does the p-value say?

The primary comparison has an unadjusted p-value of <0.001. In general, a p-value describes how unusual results at least as incompatible with a specified null hypothesis would be if that hypothesis and the analysis assumptions held. A small p-value is evidence against the null model, but it is not the probability that the null is correct, the probability that the finding occurred by chance, or a measure of effect size. The mean difference and its interval describe the estimated contrast and its precision more directly.

The word unadjusted matters because the registry record also lists secondary outcomes. The primary comparison’s p-value does not show whether a multiplicity procedure was applied; no such procedure is reported. Likewise, the record does not report the original analysis plan, so the status of the displayed comparison as prespecified or otherwise cannot be established from the registry record.

What assumptions underlie the comparison?

In general, a comparison of means relies on assumptions about the data and the method used to estimate uncertainty. Relevant considerations can include the independence of observations, how the outcome is distributed, and whether the variance estimates are suitable. A randomized parallel-group design supports an independent group comparison in principle, but the registry record does not report diagnostic checks or detailed analysis methods.

The posted comparisons are unadjusted calculations based on the group summary statistics. The record does not report a model, transformations, handling of outliers, missing-data procedures, or an analysis population. Those details would help readers evaluate whether the statistical assumptions were examined and how deviations, if any, were handled. They are not reported in the registry record.

Why do these details affect interpretation?

Statistical evidence is one part of evaluating a trial result. Randomization, masking, measurement, completeness of follow-up, analysis choices, and the relevance of the endpoint all contribute to interpretation. The registry record documents the assigned supplement and placebo and provides endpoint summaries, but it leaves several of these methodological details unreported. The numerical contrast can therefore be described clearly while the strength and scope of broader conclusions remain limited by the information available.

11. Confidence Intervals and Precision

The primary estimate is a mean difference of -75.1 mg/dL, with an interval from -81.21 to -68.99 mg/dL. The interval lies on the negative side of zero, consistent with the lower posted triglyceride mean in the octacosanol group. Its width conveys the statistical precision of this estimate under the method used. The confidence level and detailed interval method are not reported in the registry record.

Precision is not the same as validity. A relatively narrow interval cannot rule out bias from missing measurements, differences in measurement procedures, or limitations in the conduct of a study. Nor does it indicate whether the estimated difference is important to participants. The registry record does not report a threshold for clinical importance or a baseline-adjusted result.

The group standard deviations are 7.8 mg/dL in the octacosanol arm and 8.1 mg/dL in the placebo arm. These summarize within-group variability, whereas the interval describes uncertainty around the estimated contrast. The two kinds of information answer different questions and should not be conflated.

The reported p-value, <0.001, indicates that the unadjusted comparison is inconsistent with a null model of no mean difference under its assumptions. The interval adds information about the range of estimated contrasts supported by the calculation. Neither statistic captures uncertainty about follow-up completeness, the original analysis plan, multiplicity handling, or longer-term outcomes, which are not reported in the registry record.

12. Planning a Similar Trial: Sample Size

This is a planning illustration, not a re-evaluation of the original trial. It asks: if a new study wanted to detect a difference like the one observed, or a smaller one, how large would it need to be? It is deliberately not “observed power” of the finished trial, which is not a meaningful quantity.

The planning figures are participants per arm, not total events. They are illustrative calculations based on the observed effect rather than the trial’s original design assumptions. The planning assumptions are a two-sided significance level of 0.05, equal allocation between the two arms, and a normal approximation. The target effect is set to 100% of the observed effect, 75% of the observed effect, or 50% of the observed effect.

The 80% power column describes the calculated participants per arm for a hypothetical study designed to have an 80% chance of detecting the specified effect under those assumptions, if that effect and the planning model were correct. The 90% power column uses a higher chance of detection as its target and consequently can require more participants. For the primary endpoint, the planning figures are 1 participant per arm for 80% power and 1 participant per arm for 90% power at 100% of the observed effect; the corresponding figures are also 1 and 1 at 75%, and 1 and 1 at 50%.

These calculations are unusually small because they are based on the large observed contrast relative to the reported variability. They should not be treated as a recommendation for a future trial without independent design assumptions and consideration of the study’s aims and limitations. Smaller target effects require more participants, as reflected in the planning scenarios for secondary outcomes. In a graphical representation of these calculations, moving toward a smaller target effect corresponds to increasing the participant requirement under the stated assumptions.

This is not observed power. The trial’s own sample-size justification and original design assumptions are not reported in the registry record.

13. How the Sample Size Is Derived

Power is the probability that a study of a given size rejects the null hypothesis when a specific true effect exists. It depends on four things: the effect to detect, the variability of the outcome, the significance level (here a two-sided α of 0.05, so z_1−α/2 = 1.960) and the desired power (z_1−β = 0.842 for 80% and 1.282 for 90%).

Formula

n is the number of participants in each arm, Δ is the difference in means to detect and σ is the common standard deviation.

Worked calculation for this trial

1. Observed difference Δ = -75.100; pooled standard deviation σ = 7.951.
2. n = 2 × (1.96 + 0.842)² × 7.951² / -75.100² = 0.2, rounded up to 1 participants per arm for 80% power.

The smaller-effect rows in the table above repeat the same calculation with the effect multiplied by 0.75 and 0.5 (for ratios, applied to the logarithm of the ratio).

R code

alpha <- 0.05
z_a   <- qnorm(1 - alpha / 2)          # two-sided
delta <- -75.1                      # observed difference in means
sigma <- 7.95141496841914                     # pooled standard deviation
n_per_arm <- function(power, frac = 1) {
  ceiling(round(2 * (z_a + qnorm(power))^2 * sigma^2 / (delta * frac)^2, 6))
}
for (f in c(1, 0.75, 0.5))
  cat(sprintf("%3.0f%% of observed effect: n per arm = %s (80%% power), %s (90%% power)\n", 100 * f,
              format(n_per_arm(0.80, f), big.mark = ","), format(n_per_arm(0.90, f), big.mark = ",")))

# Check against R's built-in function (t-based, so very slightly larger)
cat("power.t.test:", round(power.t.test(delta = delta, sd = sigma, power = 0.80)$n, 1), "\n")

# Simulation: exact two-sample t-test using simulated means and variances
set.seed(3557476)
n    <- n_per_arm(0.80)
reps <- 20000
m_diff <- rnorm(reps, delta, sigma * sqrt(2 / n))             # difference in sample means
s2     <- sigma^2 * rchisq(reps, 2 * (n - 1)) / (2 * (n - 1))   # pooled sample variance
tstat  <- m_diff / sqrt(s2 * 2 / n)
cat(sprintf("Simulated power at n = %s per arm: %.3f (%d replicates)\n", format(n, big.mark = ","), mean(abs(tstat) > qt(0.975, 2 * (n - 1))), reps))

Output from running the code

100% of observed effect: n per arm = 1 (80% power), 1 (90% power)
 75% of observed effect: n per arm = 1 (80% power), 1 (90% power)
 50% of observed effect: n per arm = 1 (80% power), 1 (90% power)
power.t.test: 1.7 
Simulated power at n = 1 per arm: NA (20000 replicates)

The simulation draws many sets of group means and variances at the planned sample size and counts how often the two-sample t-test rejects the null. It should land close to the target power; at very small required sample sizes it can fall below it, because the normal approximation is rough there.

14. Multiplicity, Missing Data and Analysis Populations

The registry record lists one primary endpoint and three secondary outcomes. It does not report a statistical analysis plan, a hierarchy among the outcomes, or a method for controlling multiplicity. When several outcomes are assessed, the chance of an apparently notable result arising from repeated testing can increase. This makes unadjusted secondary p-values less conclusive than results evaluated under a prespecified multiplicity strategy. The primary p-value is also presented as unadjusted, and the record does not clarify whether it was part of a broader planned testing procedure.

Missing-data methods and participant flow are not reported in the registry record. Although the posted outcome summaries give 13.0 participants in each primary arm, the record does not explain whether these are all randomized participants, all participants with an available endpoint, or an analysis-defined subset. It also does not report withdrawals, reasons for missing measurements, imputation, or sensitivity analyses. As a result, it is not possible to assess the effect of missing outcome data from the registry record alone.

The record does not report analysis-population definitions, such as whether the analysis followed randomized assignment or included only participants who completed the intervention. Nor does it report a baseline-adjusted analysis, covariate adjustment, or handling of protocol deviations. The posted comparison is interpretable as an unadjusted contrast of the reported group summaries, but the population and analysis choices behind those summaries are not described.

These omissions do not establish that particular procedures were absent; they mean that those procedures are not reported in the registry record. They limit assessment of selective reporting, the role of missingness, and the extent to which the reported analyses followed a prespecified plan.

15. Safety Results

The registry reports serious adverse events as affected participants divided by participants at risk.

Deaths

Other (non-serious) adverse events

Participants with at least one non-serious event at or above the registry's 0% reporting threshold.

The adverse-event record reports zero serious adverse events in the octacosanol group and zero in the placebo group. Each arm lists 13 participants at risk for serious adverse events. The record also lists zero other adverse events in each arm and zero deaths in each arm. No serious adverse event terms are listed.

These figures describe what is recorded for this trial; they should not be taken as proof that no adverse effects can occur. The registry record does not report detailed event definitions, the duration or completeness of safety follow-up, or how events were collected and assessed. It also does not provide further descriptions of the zero-event entries. A zero count in a trial of this size and timeframe cannot establish the absence of uncommon or later events.

16. What the Result Does, and Does Not, Mean

The posted primary result is a lower mean plasma triglyceride level in the octacosanol group than in the placebo group at six days. The estimated unadjusted mean difference is -75.1 mg/dL, and its confidence interval ranges from -81.21 to -68.99 mg/dL. The secondary summaries show a consistent broad pattern across the reported oxidative-stress measures. These observations describe the endpoint values recorded for the trial and the contrasts calculated from them.

The data do not, on their own, establish that the intervention caused the differences. Randomization and double masking are design features that can strengthen comparisons, but the registry record does not report enough information to assess implementation, participant flow, missing data, or the analysis population. Baseline endpoint values are also not reported, so the posted endpoint means cannot be interpreted as within-participant change.

The result does not show whether any difference persisted beyond the six-day timeframe, how it relates to longer-term health, or whether it affected Taekwondo performance. The registry record does not report a threshold for a clinically important change or detailed measurements linking these biomarkers to health or performance outcomes. The title’s broad wording should not be read as a substitute for evaluating the specific endpoint estimates and limitations.

Likewise, zero recorded adverse events does not establish that the supplement is free of risk. The safety entries are limited to the events recorded in this trial, and follow-up details are not reported. Overall, the posted data provide an endpoint comparison and a short-term biomarker pattern, while leaving important questions about durability, broader relevance, and study conduct unresolved.

17. Why This Trial Matters Statistically

This trial is statistically interesting because it compares a dietary supplement with a placebo in a randomized, double-masked, parallel design and reports both a lipid endpoint and oxidative-stress measures. The primary contrast is large relative to the reported group standard deviations, producing a confidence interval that lies below zero and an unadjusted p-value of <0.001. The secondary outcomes point in a coherent broad direction. Together, these features make the numerical pattern easy to identify, while still requiring cautious interpretation.

The case also illustrates why statistical significance, precision, and evidential strength are different concepts. A small p-value summarizes incompatibility with a null model under specified assumptions; it does not establish importance or remove bias. The interval gives a sense of precision for the estimated contrast, but it cannot address unreported missing-data procedures, outcome selection, or analysis choices. The record’s lack of a reported multiplicity strategy is particularly relevant when several outcomes are presented.

The sample-size illustrations show another important statistical issue: planning values based directly on an observed effect may be very small when that effect is striking. Such calculations are not evidence of the study’s original planning or of observed power. The original sample-size justification is not reported in the registry record.

Finally, the short timeframe and absence of reported baseline values make it important to distinguish endpoint differences from changes over time. The trial offers a specific snapshot under a defined training and supplement schedule; it does not answer every clinical or performance question raised by its setting.

18. Limitations

• The posted summary statistics are the only data these results rest on; patient-level data, full protocols and statistical analysis plans are not available.
• Recalculated results are simple, unadjusted calculations from posted summaries. They do not replace the sponsor's prespecified analysis.

Several limitations are specific to the information recorded for this trial. The stated endpoint timeframe is six days, so the posted findings address a short period. Results at later time points are not reported in the registry record. Baseline triglyceride and secondary-outcome measurements are also not reported, preventing assessment of initial group values or within-group changes.

The registry record does not report participant eligibility details, recruitment procedures, the randomization sequence method, allocation concealment, or the people masked. It describes the trial as randomized and double-masked, but does not give enough implementation detail to evaluate those procedures. Details of adherence, protocol deviations, withdrawals, and participant flow are not reported.

The record does not identify the assay methods, timing of sample collection relative to exercise or meals, or the rationale for the selected dose and six-day schedule. It does not report the original sample-size calculation, a statistical analysis plan, or the analysis population. Missing-data handling, baseline adjustment, and multiplicity control are also not reported in the registry record.

Finally, the reported outcomes are biomarkers. The record does not provide longer-term clinical outcomes or direct measures of sports performance. The adverse-event entries show no recorded events, but safety follow-up details are not reported. These limitations define the scope of conclusions that can be drawn from the posted summaries; they do not establish that unreported procedures or measurements were never conducted.

19. Related Tutorials

20. Related Statistical Calculators

21. Sources

• ClinicalTrials.gov: Effects of Octacosanol During Taekwondo Training — NCT03557476.
• Registry record last updated 2020-11-10; status last verified 2020-11.
• Results first posted 2019-08-12.
• Data retrieved from ClinicalTrials.gov on 2026-11-09.
• Group sizes, means, event counts and sponsor-reported p-values are reproduced as posted. Effect estimates, confidence intervals and p-values not attributed to the sponsor are independently calculated from the posted summary statistics.

22. Record Summary

NCT03557476, titled Effects of Octacosanol During Taekwondo Training, is recorded as a completed randomized, double-masked, parallel-group study sponsored by Kosin University. Enrollment was 26. Participants received octacosanol or placebo during a six-day period. The primary endpoint was mean plasma triglyceride level at six days, with malondialdehyde, superoxide dismutase, and glutathione peroxidase listed as secondary outcomes.

The octacosanol group had a lower posted mean triglyceride level than the placebo group, with an unadjusted mean difference of -75.1 mg/dL and a confidence interval from -81.21 to -68.99 mg/dL. The record also reports a consistent broad direction across the secondary outcomes. Details of the original sample-size justification, analysis plan, missing-data handling, and longer-term outcomes are not reported in the registry record.